pmdazswap(1) — Linux manual page


PMDAZSWAP(1)               General Commands Manual              PMDAZSWAP(1)

NAME         top

       pmdazswap - zswap (compressed swap) PMDA

DESCRIPTION         top

       pmdazswap is a Performance Metrics Domain Agent (PMDA) which exports
       metric values about compressed swap operation, as tracked by the
       zswap Linux kernel module.

       Zswap is a lightweight compressed cache for swap pages.  It takes
       pages that are in the process of being swapped out and attempts to
       compress them into a dynamically allocated RAM-based memory pool.
       Zswap trades CPU cycles for potentially reduced swap I/O.  This
       tradeoff can also result in a performance improvement if reads from
       the compressed cache are faster than reads from a swap device.

       This PMDA exports metrics about pool size, number of pages stored,
       and various counters for the reasons pages are rejected.

INSTALLATION         top

       Install the zswap PMDA by using the Install script as root:

           # cd $PCP_PMDAS_DIR/zswap
           # ./Install

       To uninstall, do the following as root:

           # cd $PCP_PMDAS_DIR/zswap
           # ./Remove

       pmdazswap is launched by pmcd(1) and should never be executed
       directly. The Install and Remove scripts notify pmcd(1) when the
       agent is installed or removed.

FILES         top

           installation script for the pmdazswap agent

           undo installation script for the pmdazswap agent

           default log file for error messages from pmdazswap


       Environment variables with the prefix PCP_ are used to parameterize
       the file and directory names used by PCP. On each installation, the
       file /etc/pcp.conf contains the local values for these variables.
       The $PCP_CONF variable may be used to specify an alternative
       configuration file, as described in pcp.conf(5).

SEE ALSO         top

       PCPIntro(1) and pmcd(1).

COLOPHON         top

       This page is part of the PCP (Performance Co-Pilot) project.
       Information about the project can be found at ⟨⟩.
       If you have a bug report for this manual page, send it to  This page was obtained from the project's upstream
       Git repository ⟨⟩ on
       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-11.)  If you discover any
       rendering problems in this HTML version of the page, or you believe
       there is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to

Performance Co-Pilot                 PCP                        PMDAZSWAP(1)